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1.
Swiss Dent J ; 134(1): 84-104, 2024 Feb 19.
Article in German | MEDLINE | ID: mdl-38739045

ABSTRACT

The aim of the treatment of this case was to restore the form, function and aesthetics of all teeth in a patient with amelogenesis imperfecta within the age limit of the disability insurance (IV). Single-tooth zirconia crowns were selected as the treatment of choice and cemented with a conventional glass ionomer cement. For the maintenance of the oral rehabilitation and the protection of the reconstructions a michigan splint was produced and instructed to be carried over night.


Subject(s)
Amelogenesis Imperfecta , Crowns , Humans , Amelogenesis Imperfecta/rehabilitation , Glass Ionomer Cements/therapeutic use , Zirconium , Female , Male , Esthetics, Dental , Dental Prosthesis Design , Occlusal Splints
3.
Sci Rep ; 14(1): 9497, 2024 04 25.
Article in English | MEDLINE | ID: mdl-38664418

ABSTRACT

Raine syndrome (RNS) is a rare autosomal recessive osteosclerotic dysplasia. RNS is caused by loss-of-function disease-causative variants of the FAM20C gene that encodes a kinase that phosphorylates most of the secreted proteins found in the body fluids and extracellular matrix. The most common RNS clinical features are generalized osteosclerosis, facial dysmorphism, intracerebral calcifications and respiratory defects. In non-lethal RNS forms, oral traits include a well-studied hypoplastic amelogenesis imperfecta (AI) and a much less characterized gingival phenotype. We used immunomorphological, biochemical, and siRNA approaches to analyze gingival tissues and primary cultures of gingival fibroblasts of two unrelated, previously reported RNS patients. We showed that fibrosis, pathological gingival calcifications and increased expression of various profibrotic and pro-osteogenic proteins such as POSTN, SPARC and VIM were common findings. Proteomic analysis of differentially expressed proteins demonstrated that proteins involved in extracellular matrix (ECM) regulation and related to the TGFß/SMAD signaling pathway were increased. Functional analyses confirmed the upregulation of TGFß/SMAD signaling and subsequently uncovered the involvement of two closely related transcription cofactors important in fibrogenesis, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ). Knocking down of FAM20C confirmed the TGFß-YAP/TAZ interplay indicating that a profibrotic loop enabled gingival fibrosis in RNS patients. In summary, our in vivo and in vitro data provide a detailed description of the RNS gingival phenotype. They show that gingival fibrosis and calcifications are associated with, and most likely caused by excessed ECM production and disorganization. They furthermore uncover the contribution of increased TGFß-YAP/TAZ signaling in the pathogenesis of the gingival fibrosis.


Subject(s)
Abnormalities, Multiple , Adaptor Proteins, Signal Transducing , Cleft Palate , Dental Enamel Hypoplasia , Exophthalmos , Fibroblasts , Fibrosis , Gingiva , Osteosclerosis , Proteomics , Signal Transduction , Transcription Factors , Transforming Growth Factor beta , YAP-Signaling Proteins , Humans , Transforming Growth Factor beta/metabolism , Gingiva/metabolism , Gingiva/pathology , Proteomics/methods , Fibrosis/metabolism , YAP-Signaling Proteins/metabolism , YAP-Signaling Proteins/genetics , Osteosclerosis/metabolism , Osteosclerosis/genetics , Osteosclerosis/pathology , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , Transcription Factors/metabolism , Transcription Factors/genetics , Dental Enamel Hypoplasia/metabolism , Dental Enamel Hypoplasia/genetics , Dental Enamel Hypoplasia/pathology , Fibroblasts/metabolism , Fibroblasts/pathology , Microcephaly/metabolism , Microcephaly/genetics , Microcephaly/pathology , Female , Transcriptional Coactivator with PDZ-Binding Motif Proteins/metabolism , Male , Trans-Activators/metabolism , Trans-Activators/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Casein Kinase I/metabolism , Casein Kinase I/genetics , Extracellular Matrix Proteins/metabolism , Extracellular Matrix Proteins/genetics , Amelogenesis Imperfecta/metabolism , Amelogenesis Imperfecta/genetics , Amelogenesis Imperfecta/pathology , Cells, Cultured
4.
J Dent Child (Chic) ; 91(1): 38-42, 2024 Jan 15.
Article in English | MEDLINE | ID: mdl-38671566

ABSTRACT

Enamel renal gingival syndrome is a rare clinical condition characterized by the presence of amelogenesis imperfecta hypoplastic type, gingival fibromatosis and delayed tooth eruption, in addition to nephrocalcinosis with normal blood calcium levels. It is inherited as an autosomal recessive trait caused by mutations in the FAM20A gene located on chromosome 17q24.2. The purpose of this report is to describe a case of enamel renal gingival syndrome and discuss its distinct features and management.


Subject(s)
Amelogenesis Imperfecta , Nephrocalcinosis , Humans , Amelogenesis Imperfecta/complications , Amelogenesis Imperfecta/genetics , Adolescent , Fibromatosis, Gingival/genetics , Fibromatosis, Gingival/complications , Male , Female , Dental Enamel Proteins/genetics , Dental Enamel Proteins/therapeutic use
5.
Chin J Dent Res ; 27(1): 53-63, 2024 Mar 28.
Article in English | MEDLINE | ID: mdl-38546520

ABSTRACT

OBJECTIVE: To investigate FAM20A gene variants and histological features of amelogenesis imperfecta and to further explore the functional impact of these variants. METHODS: Whole-exome sequencing (WES) and Sanger sequencing were used to identify pathogenic gene variants in three Chinese families with amelogenesis imperfecta. Bioinformatics analysis, in vitro histological examinations and experiments were conducted to study the functional impact of gene variants, and the histological features of enamel, keratinised oral mucosa and dental follicle. RESULTS: The authors identified two nonsense variants c. 406C > T (p.Arg136*) and c.826C > T (p.Arg176*) in a compound heterozygous state in family 1, two novel frameshift variants c.936dupC (p.Val313Argfs*67) and c.1483dupC (p.Leu495Profs*44) in a compound heterozygous state in family 2, and a novel homozygous frameshift variant c.530_531insGGTC (p.Ser178Valfs*21) in family 3. The enamel structure was abnormal, and psammomatoid calcifications were identified in both the gingival mucosa and dental follicle. The bioinformatics and subcellular localisation analyses indicated these variants to be pathogenic. The secondary and tertiary structure analysis speculated that these five variants would cause structural damage to FAM20A protein. CONCLUSION: The present results broaden the variant spectrum and clinical and histological findings of diseases associated with FAM20A, and provide useful information for future genetic counselling and functional investigation.


Subject(s)
Amelogenesis Imperfecta , Dental Enamel Proteins , Humans , Amelogenesis Imperfecta/genetics , Calcification, Physiologic , Computational Biology , Dental Enamel , Dental Enamel Proteins/genetics , East Asian People
6.
JAMA Dermatol ; 160(5): 544-549, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38506824

ABSTRACT

Importance: Kindler epidermolysis bullosa is a genetic skin-blistering disease associated with recessive inherited pathogenic variants in FERMT1, which encodes kindlin-1. Severe orofacial manifestations of Kindler epidermolysis bullosa, including early oral squamous cell carcinoma, have been reported. Objective: To determine whether hypoplastic pitted amelogenesis imperfecta is a feature of Kindler epidermolysis bullosa. Design, Settings, and Participants: This longitudinal, 2-center cohort study was performed from 2003 to 2023 at the Epidermolysis Bullosa Centre, University of Freiburg, Germany, and the Special Care Dentistry Clinic, University of Chile in association with DEBRA Chile. Participants included a convenience sampling of all patients with a diagnosis of Kindler epidermolysis bullosa. Main Outcomes and Measures: The primary outcomes were the presence of hypoplastic pitted amelogenesis imperfecta, intraoral wounds, gingivitis and periodontal disease, gingival hyperplasia, vestibular obliteration, cheilitis, angular cheilitis, chronic lip wounds, microstomia, and oral squamous cell carcinoma. Results: The cohort consisted of 36 patients (15 female [42%] and 21 male [58%]; mean age at first examination, 23 years [range, 2 weeks to 70 years]) with Kindler epidermolysis bullosa. The follow-up ranged from 1 to 24 years. The enamel structure was assessed in 11 patients, all of whom presented with enamel structure abnormalities. The severity of hypoplastic pitted amelogenesis imperfecta varied from generalized to localized pitting. Additional orofacial features observed include gingivitis and periodontal disease, which was present in 90% (27 of 30 patients) of those assessed, followed by intraoral lesions (16 of 22 patients [73%]), angular cheilitis (24 of 33 patients [73%]), cheilitis (22 of 34 patients [65%]), gingival overgrowth (17 of 26 patients [65%]), microstomia (14 of 25 patients [56%]), and vestibular obliteration (8 of 16 patients [50%]). Other features included chronic lip ulcers (2 patients) and oral squamous cell carcinoma with lethal outcome (2 patients). Conclusions and Relevance: These findings suggest that hypoplastic pitted amelogenesis imperfecta is a feature of Kindler epidermolysis bullosa and underscore the extent and severity of oral manifestations in Kindler epidermolysis bullosa and the need for early and sustained dental care.


Subject(s)
Epidermolysis Bullosa , Humans , Male , Female , Adult , Young Adult , Child, Preschool , Adolescent , Child , Epidermolysis Bullosa/complications , Middle Aged , Longitudinal Studies , Periodontal Diseases/complications , Periodontal Diseases/epidemiology , Carcinoma, Squamous Cell/pathology , Amelogenesis Imperfecta/complications , Amelogenesis Imperfecta/genetics , Amelogenesis Imperfecta/pathology , Cohort Studies , Mouth Neoplasms/pathology , Mouth Neoplasms/complications , Gingivitis/pathology , Gingivitis/etiology , Cheilitis , Chile
7.
Int Endod J ; 57(6): 745-758, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38477421

ABSTRACT

AIM: Loss-of-function mutations in FAM20A result in amelogenesis imperfecta IG (AI1G) or enamel-renal syndrome, characterized by hypoplastic enamel, ectopic calcification, and gingival hyperplasia, with some cases reporting spontaneous tooth infection. Despite previous reports on the consequence of FAM20A reduction in gingival fibroblasts and transcriptome analyses of AI1G pulp tissues, suggesting its involvement in mineralization and infection, its role in deciduous dental pulp cells (DDP) remains unreported. The aim of this study was to evaluate the properties of DDP obtained from an AI1G patient, providing additional insights into the effects of FAM20A on the mineralization of DDP. METHODOLOGY: DDP were obtained from a FAM20A-AI1G patient (mutant cells) and three healthy individuals. Cellular behaviours were examined using flow cytometry, MTT, attachment and spreading, colony formation, and wound healing assays. Osteogenic induction was applied to DDP, followed by alizarin red S staining to assess their osteogenic differentiation. The expression of FAM20A-related genes, osteogenic genes, and inflammatory genes was analysed using real-time PCR, Western blot, and/or immunolocalization. Additionally, STRING analysis was performed to predict potential protein-protein interaction networks. RESULTS: The mutant cells exhibited a significant reduction in FAM20A mRNA and protein levels, as well as proliferation, migration, attachment, and colony formation. However, normal FAM20A subcellular localization was maintained. Additionally, osteogenic/odontogenic genes, OSX, OPN, RUNX2, BSP, and DSPP, were downregulated, along with upregulated ALP. STRING analysis suggested a potential correlation between FAM20A and these osteogenic genes. After osteogenic induction, the mutant cells demonstrated reduced mineral deposition and dysregulated expression of osteogenic genes. Remarkably, FAM20A, FAM20C, RUNX2, OPN, and OSX were significantly upregulated in the mutant cells, whilst ALP, and OCN was downregulated. Furthermore, the mutant cells exhibited a significant increase in inflammatory gene expression, that is, IL-1ß and TGF-ß1, whereas IL-6 and NFκB1 expression was significantly reduced. CONCLUSION: The reduction of FAM20A in mutant DDP is associated with various cellular deficiencies, including delayed proliferation, attachment, spreading, and migration as well as altered osteogenic and inflammatory responses. These findings provide novel insights into the biology of FAM20A in dental pulp cells and shed light on the molecular mechanisms underlying AI1G pathology.


Subject(s)
Amelogenesis Imperfecta , Cell Differentiation , Dental Enamel Proteins , Dental Pulp , Nephrocalcinosis , Osteogenesis , Tooth, Deciduous , Humans , Cells, Cultured , Dental Enamel Proteins/genetics , Dental Enamel Proteins/metabolism , Dental Pulp/cytology , Dental Pulp/metabolism , Gene Expression , Mutation , Osteogenesis/genetics
8.
FASEB J ; 38(4): e23497, 2024 Feb 29.
Article in English | MEDLINE | ID: mdl-38376916

ABSTRACT

This study investigated the possible roles of renal estrogen receptors (ER) in glomerulonephritis associated with small vessel vasculitis. The relationships of ERs were investigated in antineutrophilic cytoplasmic antibody (ANCA)-associated glomerulonephritis and immunoglobulin A (IgA) nephropathy groups, which are small vessel vasculitis subtypes with two different glomerulonephritis development pathophysiologies. The design of this study was prepared as a retrospective cohort study. The study included 42 patients with ANCA-associated vasculitis and 18 with IgA nephropathy in the small vessel vasculitis group. For the control group, intact renal tissues of 28 patients who underwent nephrectomy due to renal cell carcinoma were used. Renal biopsy samples of the groups were stained with ER beta (ß) and ER alpha (α). Tubular ER ß expression score (TERßES) median values were found to be significantly higher in ANCA- associated vasculitis (B = 0.724, OR [95%CI]: 2.064 [1.141-3.731], p = .016) and IgA nephropathy (B = 0.898, OR [95%CI]: 2.454 [1.307-4.609], p = .005) than in intact kidney tissue. It was determined that tubular ERß was most frequently localized in the distal tubule at 57.9% and the second most common in the proximal tubule at 20.4%. The expression of tubular ERß is increased in glomerulonephritis due to small vessel vasculitis. Tubular ERßs are most commonly localized in the distal tubule. Further studies are needed to understand the physiological and pathophysiological effects of altered renal ER levels in small vessel vasculitis.


Subject(s)
Amelogenesis Imperfecta , Glomerulonephritis, IGA , Glomerulonephritis , Kidney Neoplasms , Nephrocalcinosis , Vasculitis , Humans , Receptors, Estrogen , Antibodies, Antineutrophil Cytoplasmic , Retrospective Studies , Kidney , Estrogens
9.
Eur Arch Paediatr Dent ; 25(1): 85-91, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38308725

ABSTRACT

BACKGROUND: Amelogenesis imperfecta (AI) and dentinogenesis imperfecta (DI) are two groups of genetically inherited conditions resulting in abnormal enamel and dentin formation, respectively. Children and young people may be adversely affected by these conditions, with significant reduction in oral health related quality of life. Dental management of children with AI and DI is often complex, which is exacerbated by the absence of clear referral pathways and scarce evidence-based guidelines. METHOD: The need for increased knowledge and peer support led to the development of a group of UK paediatric dentists with a special clinical interest in the management of children with AI and DI. PURPOSE: The aims of this paper are to describe the establishment of an AI/DI Clinical Excellence Network (AI/DI CEN) in paediatric dentistry including outputs and future plans, and to share our collective learning to help support others anywhere in the world advance the care of people with AI or DI.


Subject(s)
Amelogenesis Imperfecta , Dentinogenesis Imperfecta , Child , Humans , Adolescent , Amelogenesis Imperfecta/therapy , Dentinogenesis Imperfecta/therapy , Quality of Life , Dentin , United Kingdom
11.
J Esthet Restor Dent ; 36(6): 881-891, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38258433

ABSTRACT

OBJECTIVE: The aim of this review was to compare various types of restorations used in children and young adults affected with amelogenesis imperfecta (AI) to determine the most effective restorative treatment. METHODS: This systematic review included randomized controlled trials, retrospective and prospective cohorts conducted on children and young adults diagnosed with amelogenesis imperfecta and written in French or English. A systematic search was conducted using four databases, namely Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via PubMed, Science Direct and Scopus, using a selection of MeSH terms: "Amelogenesis Imperfecta," "Therapeutics," "Treatment Outcome," "Adult, young," "Child," "Dental Restoration, Permanent," "Dental Restoration, Temporary," and "Esthetics, Dental." RESULTS: Out of 138 articles identified in the initial search, four articles met all the inclusion criteria. The results showed that ceramic restorations had better quality scores and longevity compared to other restorations. CONCLUSION: Ceramic restorations could be considered the restorative treatment modality of choice for AI-affected children and young adults. However, more high-quality clinical trials involving young patients affected with AI are required to evaluate and compare the outcomes of different restorative approaches. CLINICAL SIGNIFICANCE: Young patients affected with amelogenesis imperfecta usually suffer from low self-esteem, psychological problems and social avoidance, caused by the alteration of teeth such as discoloration, sensitivity, fractures and reduced size. For the dentist, selecting the appropriate restorative treatment for AI in young patients could be a veritable challenge. Therefore, it is important to have an evidence-based modality. For this reason, in this review, the different restorative approaches used in AI-affected young patients were compared to recommend the most effective treatment.


Subject(s)
Amelogenesis Imperfecta , Humans , Amelogenesis Imperfecta/therapy , Child , Dental Restoration, Permanent/methods , Young Adult , Adolescent
12.
Sci Rep ; 14(1): 445, 2024 01 03.
Article in English | MEDLINE | ID: mdl-38172607

ABSTRACT

Kohlschütter-Tönz syndrome (KTS) is a rare autosomal recessive disorder characterized by severe intellectual disability, early-onset epileptic seizures, and amelogenesis imperfecta. Here, we present a novel Rogdi mutant mouse deleting exons 6-11- a mutation found in KTS patients disabling ROGDI function. This Rogdi-/- mutant model recapitulates most KTS symptoms. Mutants displayed pentylenetetrazol-induced seizures, confirming epilepsy susceptibility. Spontaneous locomotion and circadian activity tests demonstrate Rogdi mutant hyperactivity mirroring patient spasticity. Object recognition impairment indicates memory deficits. Rogdi-/- mutant enamel was markedly less mature. Scanning electron microscopy confirmed its hypomineralized/hypomature crystallization, as well as its low mineral content. Transcriptomic RNA sequencing of postnatal day 5 lower incisors showed downregulated enamel matrix proteins Enam, Amelx, and Ambn. Enamel crystallization appears highly pH-dependent, cycling between an acidic and neutral pH during enamel maturation. Rogdi-/- teeth exhibit no signs of cyclic dental acidification. Additionally, expression changes in Wdr72, Slc9a3r2, and Atp6v0c were identified as potential contributors to these tooth acidification abnormalities. These proteins interact through the acidifying V-ATPase complex. Here, we present the Rogdi-/- mutant as a novel model to partially decipher KTS pathophysiology. Rogdi-/- mutant defects in acidification might explain the unusual combination of enamel and rare neurological disease symptoms.


Subject(s)
Amelogenesis Imperfecta , Dementia , Epilepsy , Tooth Abnormalities , Humans , Animals , Mice , Amelogenesis Imperfecta/genetics , Seizures , Mutation , Membrane Proteins/genetics , Nuclear Proteins/genetics
13.
Oral Dis ; 30(2): 537-550, 2024 Mar.
Article in English | MEDLINE | ID: mdl-36650945

ABSTRACT

OBJECTIVES: To identify etiologic variants and perform deep dental phenotyping in patients with amelogenesis imperfecta (AI). METHODS: Three patients of two unrelated families were evaluated. Genetic variants were investigated by exome and Sanger sequencing. An unerupted permanent third molar (AI1) from Patient1 and a deciduous first molar (AI2) from Patient2, along with three tooth-type matched controls for each were characterized. RESULTS: All three patients harbored biallelic pathogenic variants in FAM20A, indicating AI1G. Of the four identified variants, one, c.1231C > T p.(Arg411Trp), was novel. Patient1 possessed the largest deletion, 7531 bp, ever identified in FAM20A. In addition to hypoplastic enamel, multiple impacted teeth, intrapulpal calcification, pericoronal radiolucencies, malocclusion, and periodontal infections were found in all three patients, gingival hyperplasia in Patient1 and Patient2, and alveolar bone exostosis in Patient3. Surface roughness was increased in AI1 but decreased in AI2. Decreased enamel mineral density, hardness, and elastic modulus were observed in AI1 enamel and dentin and AI2 dentin, along with decreased phosphorus, increased carbon, and increased calcium/phosphorus and carbon/oxygen ratios. Severely collapsed enamel rods and disorganized dentin-enamel junction were observed. CONCLUSIONS: We report a novel FAM20A variant and, for the first time, the defective mineral composition and physical/mechanical properties of AI1G teeth.


Subject(s)
Amelogenesis Imperfecta , Dental Enamel Proteins , Humans , Amelogenesis Imperfecta/genetics , Amelogenesis Imperfecta/pathology , Mutation , Dental Enamel Proteins/genetics , Phosphorus , Minerals , Carbon
14.
J Pediatr Ophthalmol Strabismus ; 61(1): 59-66, 2024.
Article in English | MEDLINE | ID: mdl-37092661

ABSTRACT

PURPOSE: To report two new cases with confirmed diagnosis of Heimler syndrome and describe their systemic and ophthalmic phenotype and visual rehabilitation. METHODS: Retrospective review of medical records. RESULTS: Both siblings were diagnosed as having sensori-neural hearing loss and retinal dystrophy with exuberant intraretinal cystoid spaces and cone-rod dysfunction. The older sibling also had amelogenesis imperfecta and neither had nail abnormalities. Genetic analysis identified homozygosity for the pathogenic variant c.2528G>A p.(Gly843Asp) in the PEX1 gene in both siblings. The parents were heterozygous carriers of the variant. CONCLUSIONS: The authors report a familial case of Heimler syndrome due to biallelic PEX1 pathogenic variants that manifested as macular dystrophy characterized by cone-rod dysfunction and complicated by intraretinal cystoid spaces. Review of the literature shows that ocular phenotype is variable in patients with Heimler syndrome. [J Pediatr Ophthalmol Strabismus. 2024;61(1):59-66.].


Subject(s)
Amelogenesis Imperfecta , Eye Abnormalities , Hearing Loss, Sensorineural , Nails, Malformed , Humans , Amelogenesis Imperfecta/diagnosis , Amelogenesis Imperfecta/genetics , Amelogenesis Imperfecta/complications , Mutation , Siblings , Nails, Malformed/diagnosis , Nails, Malformed/genetics , Nails, Malformed/complications , Phenotype , Eye Abnormalities/complications , Pedigree , ATPases Associated with Diverse Cellular Activities/genetics , Membrane Proteins/genetics
15.
J Dent Res ; 103(1): 22-30, 2024 01.
Article in English | MEDLINE | ID: mdl-38058155

ABSTRACT

Amelogenesis imperfecta (AI) comprises a group of rare, inherited disorders with abnormal enamel formation. Ameloblastin (AMBN), the second most abundant enamel matrix protein (EMP), plays a critical role in amelogenesis. Pathogenic biallelic loss-of-function AMBN variants are known to cause recessive hypoplastic AI. A report of a family with dominant hypoplastic AI attributed to AMBN missense change p.Pro357Ser, together with data from animal models, suggests that the consequences of AMBN variants in human AI remain incompletely characterized. Here we describe 5 new pathogenic AMBN variants in 11 individuals with AI. These fall within 3 groups by phenotype. Group 1, consisting of 6 families biallelic for combinations of 4 different variants, have yellow hypoplastic AI with poor-quality enamel, consistent with previous reports. Group 2, with 2 families, appears monoallelic for a variant shared with group 1 and has hypomaturation AI of near-normal enamel volume with pitting. Group 3 includes 3 families, all monoallelic for a fifth variant, which are affected by white hypoplastic AI with a thin intact enamel layer. Three variants, c.209C>G; p.(Ser70*) (groups 1 and 2), c.295T>C; p.(Tyr99His) (group 1), and c.76G>A; p.(Ala26Thr) (group 3) were identified in multiple families. Long-read AMBN locus sequencing revealed these variants are on the same conserved haplotype, implying they originate from a common ancestor. Data presented therefore provide further support for possible dominant as well as recessive inheritance for AMBN-related AI and for multiple contrasting phenotypes. In conclusion, our findings suggest pathogenic AMBN variants have a more complex impact on human AI than previously reported.


Subject(s)
Amelogenesis Imperfecta , Dental Enamel Proteins , Animals , Humans , Amelogenesis/genetics , Amelogenesis Imperfecta/genetics , Dental Enamel Proteins/genetics , Dental Enamel Proteins/metabolism , Pedigree , Phenotype
16.
Spec Care Dentist ; 44(2): 465-471, 2024.
Article in English | MEDLINE | ID: mdl-37365770

ABSTRACT

BACKGROUND: KohlschüttereTönz syndrome (KTS), also called amelo-cerebro-hypohidrotic syndrome, is a very rare genetic condition, described for the first time by Kohlschutter, which typically manifests as a triad of symptoms:  amelogenesis imperfecta, infantile onset epilepsy, and intellectual disability. 47 cases were reported in English language literature since 1974-2021. CASE REPORT: A 7-year-old girl was referred for dental evaluation. Oral examination revealed yellowish color of all the teeth due to enamel hypoplasia. The radiographic exam revealed a thin layer of enamel with decreased radiopacity of the enamel compared to that of dentin. The diagnosis of amelogenesis Imperfecta was established. In addition to that, the child's parents reported that she had spasticity, epileptic seizures and psychomotor developmental delay. The association of all these features leads us to conclude to KTS. CONCLUSION: It seems that numerous cases of KTS are still undiagnosed in the world, so this paper highlights the common clinical features of Kohlschütter-Tönz Syndrome helping to an early diagnosis and more research about this condition.


Subject(s)
Amelogenesis Imperfecta , Dementia , Epilepsy , Tooth , Child , Female , Humans , Amelogenesis Imperfecta/complications , Amelogenesis Imperfecta/diagnosis , Amelogenesis Imperfecta/therapy , Dental Enamel , Syndrome
17.
J Postgrad Med ; 70(1): 56-59, 2024.
Article in English | MEDLINE | ID: mdl-37706418

ABSTRACT

We report a 2.2 year-old-boy, born of consanguineous marriage, referred for short stature, with history of neonatal death and skeletal deformities in his older sibling. Rhizo-mesomelic dwarfism was detected antenatally. Within 24 hours of birth, he developed multiple seizures. Examination revealed severe short stature, dolichocephaly, broad forehead, deep set eyes, low set ears, bulbous nose, small, irregular teeth, pointed chin, and triangular facies. He had rhizomelic shortening, stubby fingers, pes planus, and scanty hair. Neurological evaluation revealed ataxia, hypotonia, and global developmental delay. Skeletal survey radiograph revealed shallow acetabuli, short femurs and humerus, short, broad metacarpals and short cone-shaped phalanges with cupping of phalangeal bases. Clinical exome analysis revealed homozygous mutations involving the POC1A gene and the SLC13A5 gene responsible for SOFT syndrome and Kohlschutter-Tonz syndrome respectively, which were inherited from the parents. Both these syndromes are extremely rare, and their co-occurrence is being reported for the first time.


Subject(s)
Abnormalities, Multiple , Amelogenesis Imperfecta , Dementia , Dwarfism , Epilepsy , Osteochondrodysplasias , Symporters , Male , Infant, Newborn , Humans , Child, Preschool , Amelogenesis Imperfecta/genetics , Abnormalities, Multiple/genetics , Osteochondrodysplasias/genetics , Dwarfism/genetics , Dwarfism/diagnosis , Cytoskeletal Proteins , Cell Cycle Proteins
18.
Clin Genet ; 105(3): 243-253, 2024 03.
Article in English | MEDLINE | ID: mdl-37937686

ABSTRACT

Amelogenesis imperfecta (AI) represents a group of clinically and genetically heterogeneous disorders that affect enamel formation and mineralization. Although AI is commonly considered a monogenic disorder, digenic inheritance is rarely reported. In this study, we recruited two nonconsanguineous Chinese families exhibiting diverse phenotypes of enamel defects among affected family members. Digenic variants were discovered in both probands. In family 1, the proband inherited a paternal frameshift variant in LAMA3 (NM_198129.4:c.3712dup) and a maternal deletion encompassing the entire AMELX gene. This resulted in a combined hypoplastic and hypomineralized AI phenotype, which was distinct from the parents' manifestations. In family 2, whole-exome sequencing analysis revealed the proband carried a maternal heterozygous splicing variant in COL17A1 (NC_000010.11 (NM_000494.3): c.4156 + 2dup) and compound heterozygous variants in RELT (paternal: NM_032871.4:c.260A > T; maternal: NM_032871.4:c.521 T > G). These genetic changes caused the abundant irregular enamel defects observed in the proband, whereas other affected family members carrying heterozygous variants in both COL17A1 and RELT displayed only horizontal grooves as their phenotype. The pathogenicity of the novel COL17A1 splice site variant was confirmed through RT-PCR and minigene assay. This study enhances our understanding by highlighting the potential association between the co-occurrence of variants in two genes and variable phenotypes observed in AI patients.


Subject(s)
Amelogenesis Imperfecta , Humans , Amelogenesis Imperfecta/genetics , Phenotype , Frameshift Mutation/genetics , Extracellular Matrix Proteins/genetics , Biological Variation, Population , Pedigree
19.
J Med Genet ; 61(4): 347-355, 2024 Mar 21.
Article in English | MEDLINE | ID: mdl-37979963

ABSTRACT

BACKGROUND: Collagen XVII is most typically associated with human disease when biallelic COL17A1 variants (>230) cause junctional epidermolysis bullosa (JEB), a rare, genetically heterogeneous, mucocutaneous blistering disease with amelogenesis imperfecta (AI), a developmental enamel defect. Despite recognition that heterozygous carriers in JEB families can have AI, and that heterozygous COL17A1 variants also cause dominant corneal epithelial recurrent erosion dystrophy (ERED), the importance of heterozygous COL17A1 variants causing dominant non-syndromic AI is not widely recognised. METHODS: Probands from an AI cohort were screened by single molecule molecular inversion probes or targeted hybridisation capture (both a custom panel and whole exome sequencing) for COL17A1 variants. Patient phenotypes were assessed by clinical examination and analyses of affected teeth. RESULTS: Nineteen unrelated probands with isolated AI (no co-segregating features) had 17 heterozygous, potentially pathogenic COL17A1 variants, including missense, premature termination codons, frameshift and splice site variants in both the endo-domains and the ecto-domains of the protein. The AI phenotype was consistent with enamel of near normal thickness and variable focal hypoplasia with surface irregularities including pitting. CONCLUSION: These results indicate that COL17A1 variants are a frequent cause of dominantly inherited non-syndromic AI. Comparison of variants implicated in AI and JEB identifies similarities in type and distribution, with five identified in both conditions, one of which may also cause ERED. Increased availability of genetic testing means that more individuals will receive reports of heterozygous COL17A1 variants. We propose that patients with isolated AI or ERED, due to COL17A1 variants, should be considered as potential carriers for JEB and counselled accordingly, reflecting the importance of multidisciplinary care.


Subject(s)
Amelogenesis Imperfecta , Non-Fibrillar Collagens , Humans , Non-Fibrillar Collagens/genetics , Non-Fibrillar Collagens/metabolism , Autoantigens/genetics , Amelogenesis Imperfecta/genetics , Heterozygote , Phenotype , Mutation/genetics
20.
Caries Res ; 58(2): 108-114, 2024.
Article in English | MEDLINE | ID: mdl-38104541

ABSTRACT

BACKGROUND: Developmental defects of enamel (DDE) are a result of disturbances during formation and maturation of the enamel. Evaluating the most-cited DDE papers can provide important tools that point to the gaps and strengths of this important topic in dentistry. SUMMARY: This bibliometric study analyzed the 100 most-cited papers on DDE. Using a combined keyword search strategy, the 100 most-cited papers were selected in the Web of Science Core Collection. Papers that addressed any type of DDE were included. The extracted data were title, number of citations, study theme, authorship, journal, type of DDE, type of dentition (primary or permanent), type of diagnosis, study design, year, and country of publication. The bibliometric networks were generated through VOSviewer software. The 100 papers had a range from 78 to 459 citations. The main themes of studies were etiopathogenesis (53%), prevalence and incidence (22%), and diagnosis (8%). The authors with the highest number of citations were Goodman AH and Rose JC (459 citations). Most articles were published in dental journals (47%). The most studied types of DDE were fluorosis and amelogenesis imperfecta in the permanent dentition (47%). Observational (24%) and non-systematic reviews (24%) were the most common study designs and ranged from 1977 to 2019. The country with the highest number of publications was the USA (41%). KEY MESSAGES: Most of the top 100 DDE papers were about fluorosis and amelogenesis imperfecta, with top papers from three continents with English as the native language. This topic is of great importance in dentistry, and the need for further studies is highlighted, especially regarding the diagnosis and treatment of some DDEs.


Subject(s)
Amelogenesis Imperfecta , Humans , Bibliometrics , Research Design
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